Tool for assembly of pre-engraved projectiles with cartridge cases



F. R. SIMPSON 2,659,262 TOOL FOR ASSEMBLY OF PRE-ENGRAVED PROJECTILES WITH CARTRIDGE CASES Filed-May 18. 1951 Nov. 17, 1953 Patented Nov. 17, 1953 TED STATES OFFECE TOOL FOR ASSEMBLY OF FEE-ENGRAVED PROJECTILES WITH CARTRIDGE CASES 1 Claim.

This invention relates to mechanism for the assembly of a pre-engraved projectile with its case to form a complete cartridge.

The use and advantages of pre-engraved projectiles in affording greater muzzle velocity for a given charge of propellant and in greatly prolonging the life of a gun barrel by reducing friction and wear, are Well known. Where rapid fire automatic guns are used with pre-engraved projectiles, considerations of safety and satisfactory operation require that the cartridge be in a predetermined angular relation with respect to the rearward terminals of the rifiing lands and grooves at the instant that the cartridge is rammed into the breech, in order to insure that the lands or helically disposed projections upon the projectile may enter or mesh with the riding grooves of the barrel, that is, between the lands of the barrel rifiing, smoothly and with a minimum of interference.

This requirement calls, first, for a cartridge case so formed or having indexing means whereby the cartridge may be gripped or located in predetermined angular relation by the loading mechanism during loading and, secondly, for the assembly or seating of the projectile in a predetermined angular relation Within its case.

The present invention relates to the second purpose so that it is the principal object of the invention to provide a mechanism whereby the projectile may be positively guided axially into its press fit within the open end of the cartridge case so that the two are angular related in a predetermined relation in the completed cartridge. This relation, of course, is so correlated with the locating or indexing means upon the cartridge case and the loading or ramming means of the gun, that the splines or lands upon the projectile enter smoothly, and without substantial interference, between the lands of the rifting of the barrel.

Other objects and advantages will be apparent from a study of the following description in connection with the accompanying drawing.

In the drawing:

Fig. 1 is an elevation of the base, case holder, and seating mandrel.

Fig. 2 is a longitudinal axial section in a plane identified by the line 2--2 of Fig. 4 and showing a cartridge case in position and a projectile or bullet being forced downwardly towards its seat in the case.

Fig. 3 is a cross section corresponding to Fig. 2 but showing the projectile fully seated within the cartridge.

in I v Fig. 4 is a transverse cross section in a plane indicated by the line 44 of Fig. 2.

Fig. 5 is a. top plan view of the base.

Fig. 6 is a top plan View of the case holder and bullet guide.

Referring in detail to the drawing, the numeral l identifies a base having a central cylindrical recess 2 extending through its upper face only. The bottom of this recess has a key or lug 3 secured in generally radial position by means of screws i and terminating a little short of the common central axis of the base and recess. This key is generally rectangular in plan and is shaped so that it has a smooth fit within a radial channel or notch 5 in the bottom face of a case holder '6 when the latter is inserted into recess 2 in a certain angular position with respect thereto. It will be noted from Fig. 2 that the lower end of holder 6 is reduced in diameter at 1 to have a smooth fit within recess 2.

The holder '6 has a central axial bore 8 the lower portion of which is shaped to receive the case 0 of a cartridge such as a .50 caliber and its flanged head. The cartridge case, while of generally conventional form, has a radial notch or other indexing means in the rim of its head so formed as to fit smoothly over the end of key 3 when the case is inserted into the holder with its notch in alignment with and forming a continuation of channel 5 and the holder and case are inserted into recess 2 in the proper angular relation with base I. When this has been done, case C is fixed in a definite predetermined angular relation with respect to base I as will be apparent from inspection of Fig. 2.

The upper portion of bore 8 is counterbored as indicated at 8a, Figs. 2 and 3, and has a semicylindrical portion cut out, as indicated at 8,

Fig. 4. This cut-out portion may be of less depth than the counterbore, as shown in Fig. 2. A bullet index guide H! is of generally tubular form with an outside diameter smoothly fitting counterbore 8a and an axial dimension preferably equal to that of the counterbore so that when in position within the counterbore, the ends of the guide and case holder are flush. The guide ill has an integral flange Illa flush with the upper end thereof and having an axial dimension shown as equal to the depth of cutout portion 9. This flange is conveniently of a shape defined by two mutually normal radial faces lying in respective planes through the central longitudinal axis of the holder 6 so that the guide may have limited rotational adjust- 3 ment, as is clear from Fig; 4. The flange Illa has an arcuate slot H through which a set screw I2 passes into a tapped hole in holder 6 so that, by tightening the set screw, the guide may be held in angularly adjusted position.

The guide it] has a central splined bore l3. The splines extend helically with the same pitch as the splines or engraving upon the projectiles which pitch is, of course, the same as therifiing of the barrel of the gun from which the cartridges are to be fired. The helical channels in the bore l3, identified at M, Fig. 6, are shown as four in number, are equally circumferentially spaced and have an angular extent equal to 'thejlan'd's or splines. Thus, each spline and-channel has an angular or circumferential extent ct -45 in the model illustrated. I

This model is intended for usewith projectiles having four equal, equally-circumferentiallyspaced splines, one of which is identified at S, Figs. 2 and 3, where it will be noted-that the splines are chamfered or tapered at 'their'forward ends whereby only 'a small area of the forward ends remain. The rearward ends of the lands of the riding of the gun barrel as c'orrespondingly tapered so that the splines on the projectile will mesh with or enter between the lands of the barrel rifiing with a minimum likelihood of interference when the cartridge is rammed.

The necessary position of angular adjustment of index guide Iii can easily be determined by trial and after having been set by screw l2, may be made permanent'by dowels l and I6, Fig. 4, passing with a snug or driven fit into holes drilled through flange lfla into 'case holder 6.

V The use of the bullet seater will be apparent from the foregoing description. The final angular setting or adjustment of guide It] will be determined by the characteristics or construction of the gun from which the cartridges are tobe' fired. That is, in the gun, the ramming or loading mechanism has a lug or key which has generally the same dimensions as lug or key 3 and which reciprocates only, during loading and extracting movements. The cartridges are so loaded into the clip or belt that the lug or key of the gun loading mechanism will engage andgfit within the notch of each cartridge case as the cartridge is rammed into the barrel. This lug-or key of the gun loading mechanism has a :predetermined fixed angular relation with respect to the lands and groovesof the gun barrel and it is this predetermined relation which is-controlled and determined by the present tool or assembly device. This relation of course may have any angular value and will be determined by the design and construction of the gunitself. [t is only necessary that such relation be reproduced in the assembly of the projectile into its casing. Then, when the cartridge is properly engaged with the'loading or ramming'mechanism of the gun, the projectile will be so angularly related with respect to the rearward terminals of the barrel rifling that each splines will enter and fit smoothly the corresponding channel between adjacent lands of the barrel whereby the advantages of ure-engraving, as previously described, are realized to the maximum extent.

'With the index guide 10 angularly adjusted so as to give the aforementioned angular'relati'o'n 3f the cartridge case and projectile when the apertured in its lower end to receive the nose of theprojectile. The plunger is then moved downwardly'a's ihdicat'ed'in Fig. 2, to the final position "of Fig. '3wherein the base of the bullet is firmly seated in and gripped by, the forward end of the casing. Any suitable means such as stop surfaces (not shown) between plunger IT or other partof the press and holder 6, may be employed to limit and determine the proper seating of the projectile asby such surfaces coming into-contact when the bullet is in final position of assembly. Since the splines in guide ID are helically disposed about the central longitudinal axis, the projectile rotates through a small angleas it is pressed downwardly into the case. This slight rotation assists the movement of the bullet into final assembled position. It is, of course, this final position which determines the adjusted position of guide 1'0 with respect to case holder 6.

While I have described the preferred form of the invention asnow known tome, various modifications and substitutions will occur to those skilledin the art after a study of the foregoing disclosure. Thus the disclosure should-be taken in an illustrativerather than a limiting sense and itis my-desire and intention to reserve all such changes as fall within thescope of the subjoined claim.

Having now fully disclosed the invention, "what I claim and desire to secureby Letters-Patent is:

In a'tool for assemblyinga pre-engraved bullet within a cartridge case, a base having a cylindrical recess, a cartridge case holder having a central axial bore within which a cartridge case fits when inserted from the bottom of the bore, said holder being counterbored at its upper 'end and having its lower end shaped to smoothly rotatably fit-the recess in said base, said holder 7 havinga channel in-its lower end radiallyof the borea'xis, a-key fixed inthe recess of the base to fit said channel and a peripheral notch in the head of V the cartridge case when the two are inserted into said recess in predetermined angular relation,;a bullet guide rotatably fitting the counterbore in said 'holder, said guide having a splined bore to slideably receive and guide abullet into assembled position withinthecartridge case, a flange integral with saidguide and having an arcuate slot therein and a screw passing through said slot and threaded into said holder to secure the guidein fixed position of rotational adjustment withrespect to said holder.

FRANK a. SIMPSON.

References Cited in the file or this patent UNITED STATES PATENTS Number V Name Date 1 118349 Fernss l Sept. 12, 1871 683,384 Cole Sept. 24, 1901 

